修复重构后的导入错误和缺失模块

backend/app/main_graph/utils/subgraph_builder.py

@@ -6,7 +6,7 @@ Main Graph Builder - Full React Mode with Loop Reasoning
 from app.main_graph.graph import StateGraph, START, END
 from typing import Dict, Any
 
-from .state import MainGraphState, CurrentAction
+from app.main_graph.state import MainGraphState, CurrentAction
 from .react_nodes import (
     init_state_node,
     react_reason_node,
@@ -50,7 +50,7 @@ def wrap_subgraph_for_error_handling(subgraph, name: str):
             
         except Exception as e:
             # 捕获子图错误，传递给主图
-            from .state import ErrorRecord, ErrorSeverity
+            from app.main_graph.state import ErrorRecord, ErrorSeverity
             from datetime import datetime
             
             error_record = ErrorRecord(